DEVICE FOR INJECTING FOAMABLE MATERIAL INTO A MOLD AND PROCESS FOR PRODUCING FLAT FOAM COMPONENTS - Patent application

Abstract

The present invention relates to an apparatus for injecting a foamable material into a mold (27) for forming a flat foam component, the apparatus comprising a tube (31) having a first end (35) by which the tube can be connected to a nozzle (21) of an injection device, and a stream separator (33) for dividing the foamable material into at least two partial streams, the stream separator (33) being located at a second end (37) of the tube (31) opposite the first end (35). The present invention further relates to a process for producing a flat foam component using such an apparatus.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for injecting a foamable material into a mold for forming a flat foam component, and to a process for producing a flat foam component by providing an injection apparatus with a foamable material and injecting the foamable material into a mold through a nozzle.

[0002] Foam components are typically produced by injecting a foamable material into a mold. Such a foamable material can be, for example, a polymer melt containing a blowing agent or a multi-component system. When the foamable material is a multi-component system, the system typically includes at least two components that react to form a polymer, plus a blowing agent. If the blowing agent is a physical blowing agent, it evaporates due to the heat of reaction. If a chemical blowing agent is used, the blowing agent reacts with one of the components of the polymer, for example, with an isocyanate if the polymer is polyurethane, thereby forming a gas such as carbon dioxide. The foam is produced due to volume expansion resulting from the formation of the gas, either by evaporation or chemical reaction.

[0003] To form a flat foam component, particularly in a discontinuous process, a predetermined amount of foamable material is injected into a mold. The foaming agent expands in the mold, thereby completely filling the mold with foam. However, because the foamable material typically only reaches certain areas of the mold during injection, a foam component may be formed with unevenly distributed cells or cells of different sizes. This uneven distribution typically leads to a foam component with local density differences.

[0004] In order to produce foamed components with a uniform density distribution, it is known, for example from EP 3,278,949 A, to fill a mould with a reactive mixture, in which a jet of reactive mixture is injected into the mould to form a puddle in the intermediate region of the mould, a forward sliding of the puddle of reactive mixture is caused by the jet, and after the puddle has reached a predetermined position, injection of the reactive mixture is continued to overfill the mould.

[0005] WO 2013 / 164274 describes a process in which a foaming reaction mixture is introduced into a mold under variable injection pressure, which causes the reaction mixture to be injected into different areas of the mold, thus resulting in a more uniform density distribution.

[0006] Another process for injecting a reaction mixture into different areas of a mold is disclosed in EP 2,366,525, where the reaction mixture is injected into the mold at different flow rates and injection speeds to pour the reaction mixture into different deposition zones of the mold.

[0007] JP 2006-142125 A describes a process for filling a mold to produce foamed polyurethane articles using a comb nozzle with multiple holes in a straight tube. However, this nozzle is used to apply the reaction mixture onto a belt or carrier, which the comb nozzle or belt moves along. Therefore, this nozzle cannot be used to produce foamed components in a closed mold.

[0008] The object of the present invention was to provide an apparatus and process for forming foamed components that allows a simple injection process without changing injection parameters during injection and that can be easily adapted to conventional injection equipment.

[0009] This object is achieved by an apparatus for injecting a foamable material into a mold to form a flat foam component, the apparatus comprising a tube having a first end by which the tube can be connected to a nozzle of the injection apparatus, and a stream separator for dividing the foamable material into at least two partial streams, the stream separator being arranged at a second end of the tube opposite the first end, such that the at least two streams enter the mold separately.

[0010] The process for producing flat foam components is (a) providing a foamable material in an injection device; (b) injecting a foamable material into a mold through a nozzle; A device for injecting the foamable material is connected to the nozzle of the injection device such that the foamable material is divided into at least two partial streams that enter the mold.

[0011] Surprisingly, it has been shown that when a tube with a stream separator is connected to the nozzle of an injection device, flat foamed components can be produced with essentially uniform cell distribution and size.

[0012] A "flat component" in the sense of the present invention is a component having a length of at least 7 times the height of the component and a width ranging from 4 times the height of the component to 0.8 times the length of the component, the length preferably ranging from 7 to 300 times the height of the component, in particular ranging from 30 to 150 times the height of the component, and the width preferably ranging from 4 to 75 times the height of the component, preferably ranging from 5 to 25 times the height of the component.

[0013] The width and length of a component in the sense of the present invention correspond to the length of a line along the longitudinal axis of the tube between two opposite points where the line intersects the peripheral surface of the component, and to the longest line perpendicular to and intersecting the longitudinal axis of the tube between two opposite points where a line perpendicular to the longitudinal axis of the tube intersects the peripheral surface of the component, the longer line corresponding to the length of the component and the shorter line corresponding to the width of the component, and the height is the maximum height.

[0014] The flat components produced by the process of the present invention can have a base (bottom surface) of any shape, a constant height, or variable height. Preferably, the flat components have a base with an axisymmetric shape and a constant height. Particularly preferably, the flat components produced by the process of the present invention have a rectangular base and a constant height. Regardless of the shape of the base, the component can include, for example, a groove, tongue, pitch, or step along at least one side. In this regard, if the flat component has a variable height, the "base" corresponds to the intersecting plane spanned by the length and width of the component, or if the component with a variable height has a flat surface perpendicular to the component height, the "base" corresponds to this flat surface. If the component has a constant height, the "base" corresponds to one of the surfaces perpendicular to the component height. If the surfaces perpendicular to the component height have different sizes, the "side" corresponds to the larger surface. The "side" of a component with a constant height is the surface connecting the surfaces perpendicular to the component height.

[0015] The flat foam component can be, for example, a foam panel or a composite element. When the flat foam component is a composite element, it typically includes first and second sheets and a foam layer between the first and second sheets.

[0016] Flat components manufactured by the process of the invention are, for example, wall or roof elements of walk-in cooling cells, some types of doors, sandwich elements for construction, refrigerator doors, elements (walls, roofs, doors) of refrigerated trucks.

[0017] To produce a flat component, the device for injecting the foamable material is preferably positioned so that the tube outlet is directed toward the geometric center of the component. If the flat component has a rectangular base, the tube preferably enters the mold for producing the component at the center of one of the sides with the largest surface. If the flat component has a triangular base, the tube preferably enters the apex of the triangle, which apex defines the shortest height of the triangle. If the base of the flat component has four or more edges or an irregular shape, the tube preferably enters the mold at a position on the peripheral surface where a perpendicular to the longest distance between two opposing points on the edge of the component's base that intersect with the geometric center of the component intersects with the perimeter. Regardless of where the tube enters the mold, the tube is preferably positioned so that its longitudinal axis intersects the geometric center of the mold.

[0018] The nozzle through which the foamable material exits the injection device typically has a circular cross-sectional area, and therefore the tube connected to the nozzle also has a circular cross-sectional area. To accommodate sufficient cross-sectional area at the tube outlet, the stream separator preferably has an elliptical base, and to separate the foamable material into two streams, the stream separator has a straight edge opposite the base. When the stream separator has an elliptical base, the straight edge preferably lies in a plane perpendicular to the major axis of the elliptical base and the plane that intersects the major axis.

[0019] To separate the foamable material into two streams, the stream separator is further positioned with the straight edge facing the nozzle and the base of the stream separator facing the mold cavity.

[0020] The sides of the stream separator between the base and the straight edge may have flat surfaces, in which case the stream separator has the shape of an elliptical cylinder truncated at an angle to the base on either side of its major axis.

[0021] Preferably, however, the surface is curved to correspond to the edge of the base at the base and is flat in the direction of the straight edge.

[0022] To evenly separate the foamable material into two streams, the stream separator more preferably has a cross-sectional area in the shape of an isosceles triangle. If the stream separator has an oval base with curved side surfaces, each cross-sectional area perpendicular to the major axis of the oval base preferably has the shape of an isosceles triangle.

[0023] The isosceles triangle, whose base is the minor diameter of the elliptical base, can have any suitable apex angle. Preferably, the apex angle is in the range of 10° to 150°, more preferably 20° to 70°, and especially 30° to 90°. The appropriate angle depends on the length-to-width ratio of the foamed component. The smaller the length-to-width ratio, the larger the apex angle.

[0024] Depending on the shape of the mold cavity, and therefore the shape of the foamed component being produced using the apparatus for injecting the foamable material into the mold, different stream separators may need to be used.

[0025] Furthermore, in order to set the direction in which each stream is injected into the mold and to have openings through which each stream is supplied to the mold of the required size, the tube preferably includes two opposing notches at the end where the stream separator is located. Particularly preferably, the notches are symmetrical with respect to the straight edge of the stream separator. The geometric shape of the notches can be any suitable shape, for example, rectangular, triangular, or semi-elliptical or semi-circular. Particularly preferably, the notches have a semi-elliptical or semi-circular shape.

[0026] If it is intended to use a different type of injection device, it may be necessary to provide a different stream separator. For this purpose, the stream separator should be releasably (detachably) connected to the pipe, in which each type of releasable connection can be used. Such connections are, for example, threaded connections, bayonet connections, clips, latches, or spring locks. In order to easily change the stream separator, it is preferable to use clips, latches, bayonet connections, or spring locks to connect the stream separator to the pipe.

[0027] The stream separator and the pipe can be made of the same material or different materials. Suitable materials for the pipe and the stream separator may be metal, such as steel, aluminum, brass, or polymers such as PE, PP, PU, ​​PA, PC, or the pipe and the stream separator can be made of different materials. Preferably, the material from which the stream separator is made is suitable for 3D printing, extrusion, or injection molding. Particularly preferably, the pipe is made of steel or PP, and the stream separator is made of PP.

[0028] To produce a foam component, a foamable material is provided in an injection device and injected from the injection device into a mold through a nozzle. To inject the foamable material, a pipe having the device described above is connected to a nozzle for dividing the foamable material into at least two streams. After filling the mold, the foamable material hardens, thereby forming a foam. After hardening, the foam component thus formed can be removed from the mold, and new foamable material can be injected into the mold to produce the foam component.

[0029] The injection device used to inject the foamable material can be any injection device known to those skilled in the art. Preferably, the injection device used to inject the foamable material into the mold is an injection device for injecting a foamable material containing at least two components that react to form a polymer and a foaming agent. Such an injection device is, for example, a mixing head for injecting a multi-component system into the mold.

[0030] The multi-component system that can be injected into the mold to form the foam component is preferably a system that includes a mixture of two components that react to form a polymer and a blowing agent. Suitable multi-component systems are all systems in which monomers and / or oligomers are mixed and then reacted to form a polymer, and a blowing agent can be included to form a foam.

[0031] Such multi-component systems comprise, for example, at least one polyisocyanate (A), at least one isocyanate-reactive compound (B), and at least one chemical and / or physical blowing agent (C). Furthermore, the multi-component system may comprise at least one catalyst (D), stabilizers, and, optionally, flame retardants and / or other additives (E). In this case, suitable polyisocyanates (A) are, for example, methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), or hexamethylene diisocyanate (HDI), and the isocyanate-reactive compound (B) is, for example, a polyether polyol.

[0032] The polyisocyanate (A) is an aromatic polyfunctional isocyanate known in the prior art. Such polyfunctional isocyanates are known and can be prepared by methods known per se. The polyfunctional isocyanates can be used, in particular as mixtures, so that component (A) in this case contains different polyfunctional isocyanates. The polyisocyanate (A) is a polyfunctional isocyanate having two (hereinafter also referred to as diisocyanate) or more than two isocyanate groups per molecule. The isocyanate (A) is particularly selected from the group consisting of aromatic polyisocyanates, such as 2,4- and 2,6-toluene diisocyanate and the corresponding isomeric mixtures; 4,4'-, 2,4'-, and 2,2'-diphenylmethane diisocyanate and the corresponding isomeric mixtures (also known as monomeric diphenylmethane or MMDI), such as a mixture of 4,4'- and 2,4'-diphenylmethane diisocyanate; and mixtures of at least one isomer of diphenylmethane diisocyanate with higher homologs of diphenylmethane diisocyanate having at least three aromatic nuclei and at least three functional groups, also known as polyphenyl-polymethylene polyisocyanates or polymeric MDI. MDI isomers and homologs are generally obtained by distillation of crude MDI. In addition to dinuclear MDI (MMDI), polymeric MDI also includes one or more polynuclear condensation products of MDI with a functionality greater than 2, particularly 3, 4, or 5. Polymeric MDI is known and is frequently described as polyphenyl-polymethylene polyisocyanate. Mixtures of 4,4'-, 2,4'-, and 2,2'-diphenylmethane diisocyanate with polyphenylpolyethylene polyisocyanate (crude MDI), and mixtures of crude MDI with toluene diisocyanate can also be used as isocyanates (A).Particularly suitable are 2,2'-, 2,4'- or 4,4'-diphenylmethane diisocyanate (MDI) and mixtures of two or three of these isomers, 1,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-toluene diisocyanate (TDI), 3,3'-dimethyldiphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or p-phenylene diisocyanate (PPDI).

[0033] The polyisocyanate of component (A) particularly preferably comprises 2,2'-MDI, 2,4'-MDI, or 4,4'-MDI, or a mixture of monomeric diphenylmethane diisocyanates, or a mixture of monomeric diphenylmethane diisocyanates with higher nuclear homologues of MDI. The average functionality of polyisocyanates containing polymeric MDI can vary from about 2.2 to about 4, preferably from 2.4 to 3.8, and especially from 2.6 to 3.0. Multifunctional isocyanates or mixtures of two or more MDI-based multifunctional isocyanates are known and are commercially available from BASF Polyurethanes GmbH under the trade names Lupranat® M20, Lupranat® M50, and Lupranat® M70.

[0034] The isocyanate-reactive compounds (B) used may be selected from any compounds having isocyanate-reactive groups known in polyurethane chemistry, preferably compounds having an average of at least 1.5 isocyanate-reactive groups, such as hydroxyl, -NH, NH, or carboxylic acid groups, preferably NH or OH groups, in particular at least 1.5 OH groups. The average functionality of the compounds of component (B) relative to isocyanate groups is at least 1.5, preferably in the range of 1.6 to 8.0, particularly preferably 2 to 5.0, in particular 3 to 4.5.

[0035] The compound (B) having at least two isocyanate-reactive hydrogen atoms comprises at least one polyether polyol.

[0036] In a preferred embodiment, the polyether polyol preferably has a hydroxyl number of 100 to 1000 KOH / g and is prepared by alkoxylation of a starter or a mixture of starters.

[0037] Polyether polyols are prepared by known processes, for example, by anionic polymerization of one or more alkylene oxides having 2 to 4 carbon atoms using conventional catalysts.

[0038] Preferred alkoxylation catalysts are KOH and amine alkoxylation catalysts.

[0039] Suitable alkylene oxides include, for example, tetrahydrofuran, 1,3- and 1,2-propylene oxide, 1,2- and 2,3-butylene oxide, styrene oxide, ethylene oxide, preferably 1,2-propylene oxide.

[0040] The polyether polyols may have a hydroxyl number of 100 to 1000 mg KOH / g, preferably 200 to 800 mg KOH / g, particularly preferably 250 to 500 mg KOH / g.

[0041] The blowing agent (C) used to produce rigid polyisocyanurate foams preferably includes water, formic acid, and formic acid-water mixtures, which react with isocyanate groups to form carbon dioxide and carbon monoxide. These blowing agents are called chemical blowing agents because they release gas through a chemical reaction with the isocyanate groups. Additionally, physical blowing agents, such as low-boiling hydrocarbons, can also be used. Suitable physical blowing agents include, in particular, liquids that are inert to the polyisocyanate (A) and have boiling points below 100°C, preferably below 50°C, at atmospheric pressure, and therefore evaporate under the influence of the exothermic polyaddition reaction.

[0042] Usable physical blowing agents are, for example, alkanes such as heptane, hexane, n- and isopentane, preferably technical mixtures of n-pentane and isopentane, n-butane, isobutane and propane, cycloalkanes such as cyclopentane and / or cyclohexane, ethers such as furan, dimethyl ether and diethyl ether, ketones such as acetone and methyl ethyl ketone, alkyl carboxylates such as methyl formate, dimethyl oxalate and ethyl acetate, and halogenated saturated and unsaturated hydrocarbons such as methylene chloride, dichloromonofluoromethane, difluoromethane, toluene, toluene- ... Trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, and heptafluoropropane, as well as unsaturated hydrocarbons such as trifluoropropene and tetrafluoropropene, for example (HFO-1234), pentafluoropropene, for example (HFO-1225), chlorotrifluoropropene, for example (HFO-1233), chlorodifluoropropene, chlorotetrafluoropropene, and hexafluorobutene, and mixtures of one or more of these components. Tetrafluoropropene, pentafluoropropene, chlorotrifluoropropene, and hexafluorobutene are preferred, and the unsaturated terminal carbon atom has at least one chloro or fluoro substituent. Examples include 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,1,3,3-tetrafluoropropene, 1,2,3,3,3 pentafluoropropene (HFO-1225ye), 1,1,1-trifluoropropene, 1,1,1,3,3 pentafluoropropene (HFO-1225zc), 1,1,2,3,3 pentafluoropropene (HFO-1225yc), 1-chloro-2,3,3,3-tetrafluoropropene (HFO-1224yd), 1,1,1,2,3 pentafluoropropene (HFO-1225yez), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), 1,1,1,4,4,4-hexafluorobut-2-ene (HFO-1336mzz).These low boiling point liquids can also be used in mixtures with each other and / or with other substituted or unsubstituted hydrocarbons.

[0043] Organic carboxylic acids such as formic acid, acetic acid, oxalic acid, ricinoleic acid, and carboxyl-containing compounds are also suitable.

[0044] The catalysts (D) used for producing the rigid polyisocyanurate foams according to the present invention are compounds which significantly accelerate the reaction of the compounds containing reactive hydrogen atoms, in particular hydroxyl groups, of components (B) to (E) with the polyisocyanate (A).

[0045] Advantageously used compounds include, for example, basic polyurethane catalysts, tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N,N,N',N'-tetramethyldiaminodiethyl ether, bis(dimethylaminopropyl)urea, N-methyl- or N-ethylmorpholine, N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N,N-tetramethylbutanediamine, N,N,N,N-tetramethylhexane-1,6-diamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether , dimethylpiperazine, N-dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-azabicyclo(2,2,0)octane, 1,4-diazabicyclo(2,2,2)octane (Dabco), and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine, dimethylaminoethanol, 2-(N,N-dimethylaminoethoxy)ethanol, N,N',N''-tris(dialkylaminoalkyl)hexahydrotriazines such as N,N',N''-tris(dimethylaminopropyl)-s-hexahydrotriazine, and triethylenediamine.

[0046] However, further suitable catalysts include metal salts such as iron(II) chloride, zinc chloride, lead octoate and tin salts such as tin dioctoate, tin diethylhexanoate and dibutyltin dilaurate, and mixtures of tertiary amines and metal salts, especially organotin salts. Contemplated catalysts further include amidines such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali metal hydroxides such as sodium hydroxide and alkali metal alkoxides such as sodium methoxide and potassium isopropoxide, alkali metal carboxylates, and alkali metal salts of long-chain fatty acids having from 8 to 20 carbon atoms and optionally pendant OH groups.

[0047] Contemplated catalysts further include incorporable amines, preferably amines having -OH, -NH, or -NH2 functional groups, such as ethylenediamine, triethanolamine, diethanolamine, ethanolamine, and dimethylethanolamine. Incorporable catalysts can be considered compounds of component (B) as well as compounds of component (D).

[0048] It is also possible to carry out the reaction without a catalyst, in which case it is common to take advantage of the catalytic activity of an amine-initiated polyol.

[0049] Catalysts contemplated for the trimerization reaction of excess NCO groups with one another further include isocyanurate-forming catalysts, such as ammonium ion salts or alkali metal salts, especially ammonium or alkali metal carboxylates, either alone or in combination with tertiary amines. The formation of isocyanurates results in flame-retardant PIR foams, which are preferably used in rigid foams for technical applications, for example, in the construction industry as insulating sheets or sandwich elements.

[0050] The reaction mixture for producing the polyisocyanate foams according to the invention may optionally be mixed with further auxiliaries and / or additives (E), including, for example, surface-active substances, foam stabilizers, cell regulators, fillers, light stabilizers, dyes, pigments, hydrolysis inhibitors, fungistatic and bacteriostatic substances.

[0051] In a preferred embodiment, components B through E are mixed to form the isocyanate-reactive component.

[0052] To produce a foamed component, typically each component is fed separately into the mixhead cavity and then injected into a mold by driving a piston into the mixhead cavity, whereby the mixture formed in the cavity is injected into the mold through the mixhead nozzle.

[0053] Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. [Brief explanation of the drawings]

[0054] [Figure 1] 1 shows a schematic representation of a process for manufacturing a foam component. [Figure 2] 1 shows a top view of an apparatus of the present invention for injecting a foamable material. [Figure 3] 1 shows a cross-sectional view of an apparatus of the present invention for injecting a foamable material. [Figure 4] 1 shows a side view of an apparatus of the present invention for injecting a foamable material. [Figure 5a] 1 shows a tube of the device of the present invention for injecting foamable material. [Figure 5b] 5a shows the tube of FIG. 5a in a position rotated by 90°. [Figure 6a] 1 shows a stream separator of an apparatus of the present invention for injecting a foamable material. [Figure 6b] 6b shows the stream separator of FIG. 6a in a position rotated by 90°. [Figure 7] 1 shows the distribution of foamable material in a mold.

[0055] FIG. 1 shows a schematic representation of a process for producing a foam component.

[0056] To produce a foam component from a multi-component system, in particular a two-component system, a first component is provided in a first container 1 and a second component is provided in a second container 3. The first container 1 is connected to a mixhead 5 by a first connecting line 7, and the second container 3 is connected to the mixhead 5 by a second connecting line 9. The first connecting line 7 comprises a first dosing unit 11 for dosing the first component into the mixhead 5, and the second connecting line 9 comprises a second dosing unit 13 for dosing the second component into the mixhead 5. In the mixhead 5, the first and second components are mixed, and a blowing agent 15 is also added to the mixhead 5 to produce a foam.

[0057] In the mix head 5, the components are mixed and then injected through a nozzle 21 into a mold 27. In the mold 27, the mixture containing the first and second components cures to form a polymer. The blowing agent causes the polymer to form a foam.

[0058] To ensure uniform distribution of the foam cells, a foamable material injection device is used that includes a tube and a stream separator. Such an apparatus is shown in top view in Figure 2, cross-sectional view in Figure 3, and side view in Figure 4.

[0059] The device 29 for injecting the foamable material comprises a tube 31 and a stream separator 33. The tube 31 has a circular cross-sectional area and is connected at a first end 35 to the nozzle 21 of the mixing head 5. At a second end 37 opposite the first end, the stream separator 33 is connected to the tube 31.

[0060] 2, the stream separator 33 has an elliptical base 39. By using an elliptical base, the foamable material is redirected at a smaller angle rather than 90°, and therefore has an oblique flow direction relative to the longitudinal axis 41 of the tube.

[0061] To divide the foamable material into two partial streams, the stream separator 33 has a straight edge 43. The stream separator 33 is positioned in the tube 31 so that the straight edge 43 faces the nozzle 21 of the mixhead 5. The base 39 of the stream separator 33 therefore faces towards the mold 27.

[0062] To avoid a reduction in the cross-sectional area through which the expandable material flows, notches 45 are provided in the tube 31. The notches 45 preferably have a semicircular or semi-elliptical shape and are positioned so that a line connecting the uppermost points 47 of the notches 45 extends perpendicular to the straight edge 43 of the stream separator 33.

[0063] In addition to the geometric shapes shown here, the tubes can have any other cross-sectional shape, such as oval, rectangular, square, or any other shape. However, because nozzles of injection devices such as mixing heads are typically circular, it is preferable to use tubes with a circular shape. The base of the stream separator 33 can have any suitable shape other than the oval shown, such as circular, rectangular, or square. Therefore, the shape of the base of the stream separator 33 depends on the cross-sectional shape of the tube 31. If the tube has a circular cross-sectional shape, it is preferable to use a stream separator 33 with an oval base. If a tube with an oval cross-sectional shape is used, the stream separator 33 can also have an oval base or alternatively a circular base. If a tube with a square cross-sectional shape is used, it is preferable to use a rectangular stream separator. If a rectangular tube is used, the base of the stream separator can have a rectangular or square shape. Here, rectangular means a rectangle other than a square.

[0064] Furthermore, the notch 45 may also have any other shape, such as a triangle, a rectangle, or a square, but preferably has the shape of a semicircle, a semi-ellipse, or a circle segment to avoid the foam material accumulating at the corners of such shapes.

[0065] Surfaces 48 of stream separator 33 can be flat or curved. Whether surfaces 48 are flat or curved, it is preferred that the cross-sectional shape of stream separator 33 at the minor diameter of the elliptical base have the shape of an isosceles triangle. Preferably, surfaces 48 of stream separator 33 are curved so that each cross-sectional shape of stream separator 33 perpendicular to the major diameter of the elliptical base has the shape of an isosceles triangle.

[0066] The isosceles triangle having the minor diameter of the elliptical base as its base may have any suitable apex angle, preferably in the range of 10° to 80°, more preferably in the range of 20° to 70°, and particularly preferably in the range of 30° to 60°.

[0067] The tube 31 of the device of the invention for injecting the foamable material into the mould is shown in more detail in Figures 5a and 5b.

[0068] In particular, to easily change the stream separator 33, it is preferred to releasably (detachably) connect the stream separator 33 to the pipe 31. Such a releasable connection is, for example, a threaded connection, a bayonet connection, or a connection having a latch, clip, or spring lock. In the embodiment shown in Figures 5a to 6b, the stream separator 33 is connected to the pipe by a clip. To connect the stream separator 33 to the pipe 31, the pipe 31 is provided with a recess 49 into which the clip of the stream separator 33 engages. It is important that the recess does not form an opening in the wall of the pipe to avoid the foamable material leaving the pipe at the location of the recess 49.

[0069] A stream separator 30 that can be attached to the tube 31 shown in Figures 5a and 5b is shown in Figures 6a and 6b.

[0070] To attach the stream separator to the pipe, the stream separator 33 includes a first clip 51 and a second clip 53. Each clip 51, 53 includes a leaf spring terminating in a thickened portion 55 sized to fit within the recess 49 in the pipe 31.

[0071] This design allows the stream separator 33 to be easily modified depending on the shape of the mold and foamed component being produced.

[0072] The distribution of foamable material in the mold is shown in Figure 7. Due to the stream separator, the foamable material is not injected parallel to the axis of the tube, but is split into two partial streams. Each stream forms a puddle 57 in the mold 27, which grows during the injection of the foamable material.

[0073] After the foamable material is injected into the mold, the components in the foamable material begin to react, thereby forming a polymer. The blowing agent fills the entire mold with foam. Experiments using the apparatus of the present invention to inject foamable material into a rectangular mold have shown that the use of the stream separator 33 achieves a much more uniform cell distribution and foam density distribution than when using a tube without a stream separator.

[0074] When the foamable material is injected without a foam-injecting device, the density of the foam in the center of the foam component is significantly higher than at the edges. However, when a foam-injecting device is used, a uniform density distribution can be achieved. [Explanation of symbols]

[0075] 1. First container 3 Second container 5 Mixing Heads 7 First connecting line 9 Second connecting line 11 First insertion unit 13 Second insertion unit 15 Foaming Agent 21 nozzles 27-inch 29 Apparatus for injecting foamable materials 31 tube 33 Stream Separator 35 first end of tube 31 37 second end of tube 31 39 Base of stream separator 33 41 longitudinal axis of tube 31 43 Straight edge of stream separator 33 45 Notch 47 Highest point 48 Surface of Stream Separator 33 49 Recess 51 First Clip 53 Second Clip 55 Thickening 57 Puddle

Claims

1. 1. An apparatus for injecting a foamable material into a mould (27) to form a flat foam component, comprising: a tube (31) having a first end (35) by means of which the tube can be connected to a nozzle (21) of an injection device; a stream separator (33) for dividing the foamable material into at least two partial streams; The stream separator (33) is disposed at a second end (37) of the tube (31) opposite the first end (35) so that the at least two streams enter the mold (27) separately.

2. 2. The apparatus of claim 1, wherein the stream separator (33) has an oval base (39) and a straight edge (43) opposite the base (39).

3. 3. Apparatus according to claim 1 or 2, wherein the stream separator (33) has a cross-sectional area in the shape of an isosceles triangle.

4. 4. Apparatus according to any one of claims 1 to 3, wherein the stream separator (33) has the shape of an elliptical cylinder truncated obliquely on either side of the major axis relative to the base.

5. 5. Apparatus according to any one of claims 1 to 4, wherein the tube (31) is provided with two opposing notches (45) at the end where the stream separator (33) is located.

6. 6. The device of claim 5, wherein the notch (45) is symmetrical with respect to the straight edge (43) of the stream separator (33).

7. 7. Apparatus according to any one of claims 1 to 6, wherein the stream separator (33) is releasably connected to the pipe (31).

8. 8. The apparatus of claim 7, wherein the stream separator (33) is connected to the tube by a clip, a latch, a bayonet coupling, or a spring lock.

9. 9. Apparatus according to any one of claims 1 to 8, wherein the injection device is a mixhead (5) for injecting a multi-component system into the mould (27).

10. 1. A process for producing a flat foam component, comprising: (a) providing a foamable material in an injection device; (b) injecting said foamable material into a mold (27) through a nozzle (21); 10. A process in which a device for injecting a foamable material according to any one of claims 1 to 9 is connected to the nozzle (21) of the injection device, such that the foamable material is split into at least two partial flows which enter the mould.

11. 11. The process of claim 10, wherein the foamable material is multi-component.

12. 12. The process of claim 11, wherein the multi-component system comprises at least one polyisocyanate, at least one isocyanate-reactive compound, and at least one chemical and / or physical blowing agent.

13. 13. The process of any of claims 10 to 12, wherein the flat foam component is a rectangular foam plate.

14. 14. The process of any of claims 10 to 13, wherein the flat foam component is a composite element comprising first and second sheets and a foam layer between the first and second sheets.

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